Cenozoic Geodynamic Evolution of the Western Mediterranean Domain: A View from the Neogene Peri-Tyrrhenian Basins

F. Roure, L. Montadert, C. Muller

Biostratigraphic and structural studies of synorogenic Neogene deposits in the southern Apennines, Calabria, and Cicily are compared to similar data from Sardinia and the Tyrrhenian Sea to trace the geodynamic evolution of the western Mediterranean domain.

During the more general European-African collision, the western border of the Apulian plate was progressively deformed, giving rise to the Apennines. Eroded materials have subsequently been trapped in three distinct environments: in the flexural basin toward the foreland, in piggy-back basins on top of the already deformed nappes, and in back-arc basins.

From Late Cretaceous to Eocene time, northwest-verging Alpine deformations occurred in Sardinia and Corsica due to the closing of the Neotethys sea. Southeast-verging Apenninic deformations started later with the closing of a remaining oceanic domain (Ligurian units) and the collision of Calabria and Apulia. Attribution of synorogenic sequences from the internal Apenninic nappes to piggy-back or foredeep environments is thus crucial for dating the closure of this post-Eocene paleo-Tyrrhenian basin. Langhian turbidites are the oldest foredeep deposits on the western Apulian platform. Serravallian to Pliocene piggy-back deposits lie on the Calabrian allochthon. In between, the Ligurian paleo-oceanic nappes show a major unconformity between upper Eocene-Oligocene and Burdigalian-Serravallian sequences. The collision could thus be either Aquitanian-early Burdigalian or Serravallian in age, with the older age more likely when compared with calc-alkaline volcanism and deformation in Sardinia or the end of the Provencal basin's opening.

In the Tyrrhenian Sea, block tilting started in late Tortonian-Messinian time, but the true oceanic crust is mainly Pliocene-Quaternary. Thus, it is contemporaneous with major shortening in the Apennines, which involved subduction of the Apulian continental lithosphere and progressive deformation of the Puglia platform.

AAPG Search and Discovery Article #91032©1988 Mediterranean Basins Conference and Exhibition, Nice, France, 25-28 September 1988.